sutty-base-jekyll-theme/_packs/controllers/cart_contact_controller.js

import { CartBaseController } from "./cart_base_controller";

export default class extends CartBaseController {
  static targets = ["form", "username"];

  connect() {
    if (!this.hasUsernameTarget) return;
    if (!this.hasFormTarget) return;

    this.formTarget.addEventListener("focusout", (event) => {
      if (!this.formTarget.checkValidity()) {
        this.formTarget.classList.add("was-validated");
        return;
      }

      this.formTarget.classList.remove("was-validated");

      const username = this.usernameTarget.value.trim();
      if (username.length === 0) return;

      this.email = username;
    });
  }
}